2016-12-10T01:14:44ZFabrication of ISFET microsensor by diffusion-based Al gate NMOS process and determination of its <i>p</i>H sensitivity from transfer characteristicshttp://nopr.niscair.res.in/handle/123456789/13610
Title: Fabrication of ISFET microsensor by diffusion-based Al gate NMOS process and determination of its <i>p</i>H sensitivity from transfer characteristics
Authors: Khanna, V K
Abstract: The present paper describes the fabrication of ISFET (Ion-Sensitive Field-Effect
Transistor) by a four-mask, thermal diffusion-based process. The sequence of
physical and chemical processes for ISFET fabrication has been elaborated. In
the first photomasking step, the regions for source and drain diffusion have
been opened. The second photolithography defined the gate area. In the third
photolithographic step, contact windows have been opened, and in the fourth
photolithographic step, the metal pattern has been delineated. After completion
of the fabrication process, the wafer has been diced into chips, which have
been mounted on ceramic substrates to provide electrical connections for
source, drain and substrate. Except for the gate region, the whole chip and
wire bonds have been protected with insulating epoxy. For process
characterization, current-voltage characteristics of MOSFET test devices
simultaneously fabricated on the same wafer have been measured for gate-source
voltages from –5 to +5 V. These were found to be <i style="">N</i>-channel, depletion-mode devices indicating similar behaviour for
ISFETs. The <i style="">p</i>H-response of ISFET has
been evaluated by drawing its <i style="">I</i><sub>DS</sub>-<i style="">V</i><sub>GS</sub> characteristics after
immersion in standard buffer solutions and applying the gate-source voltage
through Ag/AgCl reference electrode. From these transfer characteristics, <i style="">p</i>H-sensitivity of ISFET has been
determined by finding the gate-source voltage necessary to ensure constant <i style="">I</i><sub>DS</sub>, <i style="">V</i><sub>DS</sub> condition. Technological shortcomings of this work
have also been pointed out, and necessary remedial measures have been
suggested.
Page(s): 199-2072012-03-01T00:00:00ZVersatile current-mode universal biquadratic filter using plus-type dual-output ICCIIshttp://nopr.niscair.res.in/handle/123456789/13609
Title: Versatile current-mode universal biquadratic filter using plus-type dual-output ICCIIs
Authors: Chen, Hua-Pin
Abstract: In this paper, a
versatile three-input and three-output universal current-mode biquadratic
filter is proposed. The circuit employs three plus-type dual-output inverting
second-generation current conveyors (DO-ICCIIs) as active elements together
with three grounded resistors and two grounded capacitors. The proposed
configuration exhibits high-output impedance which is important for easy
cascading in the current-mode operations. It can be used as either a
single-input three-output or three-input two-output circuit. In the operation
of single-input and three-output circuit, the lowpass, bandpass and bandreject
can be realized simultaneously while the highpass filtering response can be
easily obtained by connecting appropriate output current directly without using
additional stages. In the operation of three-input and two-output circuit, all
five generic filtering functions can be easily realized by selecting different
three input current signals. The filter permits orthogonal controllability of
the quality factor and resonance angular frequency and no component matching
conditions or inverting-type input current signals are imposed. All the passive
and active sensitivities are low. Post-layout simulations are based on using
TSMC 0.18μm 1P6M CMOS
process technology and supply voltages ±0.9V to verify the theoretical
analysis.
Page(s): 188-1982012-03-01T00:00:00ZModification and designing of electrodeposited polypyrrole film for optoelectronic applicationshttp://nopr.niscair.res.in/handle/123456789/13608
Title: Modification and designing of electrodeposited polypyrrole film for optoelectronic applications
Authors: Sharma, I D; Sharma, V K; Dhawan, S K; Saini, P K
Abstract: The electrodeposited polypyrrole (PPY) film over ITO coated glass substrate
has been prepared and its current voltage response using Schottky emission
theory has been analyzed. The electrodeposition of PPY has ben carried out by
electrochemical polymerization of 0.2 M pyrrole monomer and cycling the potential
between -0.2V to 0.8 V at a scan rate of 20mV/s using KCl as supporting
electrolyte. The formation of polymer has been confirmed by X-ray diffraction
and FTIR measurements whereas the surface morphology has been observed using
scanning electron microscope. The band gap of PPY film has been calculated
using UV visible spectroscopy and found to be 2.4 eV. In addition, the
current-voltage response of deposited film was also recorded to evaluate its
electronic attributes such as barrier height (Ø<sub>B</sub>) and constant
factor (β). The results revealed the Ø<sub>B </sub>and β values of 0.314 eV and
1.72´10<sup>-4</sup>, respectively. These films may have potential applications
in electronic and optoelectronic sensing devices.
Page(s): 184-1872012-03-01T00:00:00ZDielectric behaviour of aprotic polar liquid dissolved in non-polar solvent under static and high frequency electric fieldhttp://nopr.niscair.res.in/handle/123456789/13607
Title: Dielectric behaviour of aprotic polar liquid dissolved in non-polar solvent under static and high frequency electric field
Authors: Sahoo, S; Middya, T R; Sit, S K
Abstract: Dielectric behaviour of aprotic polar liquids (<i style="">j</i>) like N,N dimethylformamide (DMF), N,N dimethylacetamide (DMA) and acetone (Ac) has been studied under static as well as 9.987, 9.88 and 9.174 GHz electric field employing Debye theory of polar-non polar liquid mixture in terms of measured <i style="">ε</i>'<i style=""><sub>ij</sub></i> and imaginary <i style="">ε</i>"<i style=""><sub>ij</sub></i> part of complex relative permittivity <i style="">ε<sub>ij</sub></i>*, static ε<sub>0ij</sub> and high frequency <i style="">ε</i><sub>∞<i style="">ij</i></sub> for different <i style="">w</i><sub>j</sub>’s of solute dissolved in non polar solvent at 27°C temperature. Double relaxation times τ<sub>2</sub> and τ<sub>1</sub> due to whole molecule and part of the polar molecule have also been estimated analytically using the complex high frequency orientational susceptibility <i style=""><img src='/image/spc_char/lembda.gif' border=0><sub>ij</sub></i>* (=<i style=""> ε<sub>ij</sub>*</i><i style="">-ε</i><sub>∞<i style="">ij</i></sub>) from measured data for DMF and DMA in C<sub>6</sub>H<sub>6</sub> and CCl<sub>4</sub> as well as acetone in C<sub>6</sub>H<sub>6</sub> and CCl<sub>4</sub> solvent, respectively at 27°C. Out of the six systems, three systems show double relaxation time τ<sub>2</sub> and τ<sub>1</sub> and dipole moment μ<sub>2</sub> and μ<sub>1</sub>. The estimated μ’s and <i style="">τ</i>’s agree excellently well with the reported and measured values from ratio of slope and linear slope method. The dipole moments μ<sub>0s</sub>’s in static electric field are also compared with <i style="">μ<sub>j</sub></i>’s in <i style="">hf </i>method. The relative contributions <i style="">c</i><sub>1</sub> and <i style="">c</i><sub>2</sub> due to <i style="">τ</i><sub>1</sub> and τ<sub>2</sub> have been calculated from Fröhlich equation as well as graphical plot of <img src='/image/spc_char/lembda.gif' border=0>'<sub>ij</sub>/<img src='/image/spc_char/lembda.gif' border=0><sub>0ij</sub> -w<sub>j</sub> and <img src='/image/spc_char/lembda.gif' border=0>''<sub>ij</sub>/<img src='/image/spc_char/lembda.gif' border=0><sub>0ij</sub> -w<sub>j</sub> curve at <i style="">w</i><sub>j</sub>→0. Solute-solute and solute-solvent molecular associations are ascertained in different molecular environment.
Page(s): 175-1832012-03-01T00:00:00Z